The study explores a novel engineering paradigm that aims to augment the cost and carbon analysis of steel building structures. Cost and carbon functions were developed specifically for this purpose including raw material, fabrication, design, fire protection, and erection components. A customised computational model for the analysis of structural alternatives was investigated. The proposed model was tested in an actual building case where several benchmark designs were computed. The outputs from the model were compared with a small number of actual design alternatives which were developed by engineering practitioners. The proposed method can significantly increase the understanding of the design space’s boundaries as the computed solutions have exhibited improved cost and carbon performance compared to actual designs.